Loop-taker mechanism for sewing machines



July 13, 1943. w. MYERS 2,324,418

LOOP-TAKER MECHANISM FOR SEWING MACHINES Filed Dec. 4, 1941 grime/HM Zdaltf 1/ yers Patentcd July 13, 1943 UNITED STATES PATENT OFFICE LOOP-BAKER mncnamsm Fon snwmc Walter Myers, Bridgeport, Coma, asslgnor to The Singer Manufacturing N. 1., a corporation of New Jersey Application December 4, 1941, Serial No. 421,528

' (oi. ifs-m) comm.

This invention relates to loop-taker mechanisms for sewing machines and more particularly to loop-taker mechanisms of the vertical-axis rotary hook type, i. e., of the type in which the rotary hook rotates about an axis substantially parallel to the path of reciprocation of the sewing machineneedle.

The present invention has for its primary obiect to facilitate replacement of a sewing machine rotary hook, as for example a worn-out or a damaged, rotary hook. A further object of the invention is to facilitate assembly of a rotaryhook actuating. mechanism in a supporting bracket of the sewing machine. Other and more specific objects of the invention will be apparent from the following description and'claims.

The invention consists in the devices, combinations and arrangements of the parts of a rotary hook actuating mechanism as hereinafter described in connection with the accompanying drawing, in which:

Fig. 1 represents an enlarged vertical section,

partly in front elevation, of a portion of a sewing machine containing the improved rotary-hook actuating mechanism. Fig. 2 represents a reduced vertical-section, partly in side elevation, of a slightly modified form of the rotary hook mechanism, the rotary hook and its shaft being omitted and the section beingtaken transversely of Fig. 1. Fig. 3 is a top-plan view of a conventional ball-bearing abutment ring. Fig. 4 is a top-plan view of a substitute sectional abutmentring The present invention is in the nature of an improvement in the vertical-axis rotary hook mechanism of my prior U. 8. Patent No. 2,236,- 830, April 1, 1941. The sewing machine has the usual frame-bed I provided with work-supporting slide-plates 2 and 9, and with a throat-plate 4 disposed between said slide-plates.

Depending from the frame-bed l is a lug 9 provided with a horizontally apertured bearingbushing 9. A loop-taker and feed actuating shaft 'l is rotatably journaled in the bearing-bushing to extend horizontally lengthwise of the bed l. Carried by the rotary shaft 1 is a feed-lift eccentric 9 engaged by a feed-bar 9 provided with a feed-dog Ill. The feed-dog ill operates through feed-slots I I in the throat-plate 4 and is actuated to cooperate, in the usual manner, with one or more endwise reciprocatory and laterally vibratory thread-carrying needles l2 in advancing the work. The feed-dog I0 is opposed by the usual spring-depressed presser-foot l9.

Complemental to the right hand needle l2, in

Company, Elizabeth;

' ll of the vertical-axis type, i. e., of the type in which the hook rotates about an axis substantially parallel to the needle l2. As more fully disclosed in my prior Patent No. 2,236,830, the rotary hook has a cup-shaped body including a bottom wall II and a generally cylindrical side wall I 9 provided with aneedle-thread loop seizing beak i1. Journaled in the side wall of the rotary hook body is a thread-carrier l9 restrained against rotation with the rotary hook.

The bottom wall ii of the rotary hook has a depending hub-flange l9 preferably integral with a vertically disposed rotary-hook shaft 20 provided with a longitudinal bore 2|. The bore 2| of the hook-shaft extends through the bottom wall I! and its hub-flange l9 of the hook-body,

and the upper end of said bore terminates in a countersink 22 in the inner face of the hook bottom wall II. The hook-shaft bore 2| opens into an enlarged counterbore 23 formed in the lower portion ,of the hook-shaft 29. Disposed in said counterbore 29 is the reduced stem 2l of an eccentric 29 held in engagement with the lower end of the shaft 20 by a screw 29. To this'end, the screw 2i is passed downwardly through the bore 2| of the hook-shaft and is threaded into the stem 24 of the eccentric 25, the head 29' of said screw being disposed in the countersink 22 of the hook-body. The eccentric 25 is locked to the hook-shaft 20 for rotation in timed relation therewith by means of a pin 21 extending transverselythrough the stem 24 of the eccentric and entering suitable notches, as 29, in the. lower end of the hook-shaft.

The hook-shaft 29 is rotatably supported by a bracket. or hook-saddle 29 which is disposed The lower portion of the opening 35 of the lower wall 92 is enlarged to provide a threaded counterbore 29.

Detachably secured by a screw 91 upon the hook-shaft 20, intermediate the ends thereof, is the hub 98 of a spiral pinion-gear 99. The hub 39 of the pinion-gear comprises, in effect, a tuthe formation of lock-stitches, is a rotary hook bu ar s eeve havin t e p ion-se is intermediate the ends of the sleeve. The hub-sleeve II has diametrically reducedend-extensions 44 and 4|, 'upon each of which is force-fitted the inner race-ring of a ball-bearing 42. The outer race-ring of the upper ball-bearing 42 is slipfltted into the bracket-opening 52 of the upper bracket-wall 2i, and the outer race-ring of the lower ball-bearing 42 is similarly fitted into the opening 35 of the lower bracket-wall 22. The outer race-ring of the lower ball-bearing 42 is circumferentially grooved to receive a conventional split abutment-ring 43 adapted to engage the bracket-shoulder 44 formed by counterbcring the lower bracket-wall opening 25. The assembly unit, comprising the pinion-sleeve 24 and the ball-bearings carried thereby is vertically positioned in the bracket 25 by a screw-plug 45 threaded into the counterbcre 35 of the bracketwall 32 to hold the abutment-ring 42 in engagement with the bracket-shoulder 44. The screwplug 45 may be suitably locked by a screw 45, Fig. 2.

The bracket-cavity 30 is closed by a detach able end-closure plate 41 and access to the pininn-gear securing screw 51 is aflorded through an aperture 48 in the front wall of the bracket 25, said aperture 48 being normally closed by a screw 45. The pinion-gear 39 is engaged, in the usual manner, by a spiral-gear 50 having its hub suitably secured upon the actuating shaft 1.

As more fully described in my prior Patent No. 2,236,830, the eccentric 25 engages the fork of a crank-arm 52 carried by the lower end of a vertically disposed rock-shaft 53. The rock-shaft 53 is journaled eccentrically in a bushing 54 adjustably secured in the bracket 29 by a screw 55. At its upper end, the rock-shaft 53 carries escapement-fingers, as 58, adapted to enter apertures, as 51, provided in the thread-carrier l8, thereby to restrain the thread-carrier against rotation with the rotary hook. Detach'ably secured upon the bottom wall of the supporting bracket 29 is a dished closure-plate 54 which houses the hook-shaft eccentric 25 and the crank-arm 52 actuated thereby, said closureplate also functioning as an oil-holding reservoir.

The wall 3| of the supporting bracket 25 is counterbored in the upper side thereof to form an annular recess 59 entered by the flange IQ of the rotary hook. Disposed in the recess 58 to overlie the upper ball-bearing 42 is a circular trough 60 having a central clearance aperture 6| for the hook-shaft 20; said trough 50 functioning as an oil-well.

Depending from the rotary-hook flange I8 is a tubular scoop 62 having its open lower end disposed in close proximity to the bottomwall of the oil-well 80. As more fully illustrated and described in my prior U. S. patent application Seria1 No. 374,421,11led Jan. 15, 1941, the tubular scoop 62 functions during the operation of the machine to pick up oil from the well 50; the oil being supplied to said well through an aperture 63 in the side wall of the oil-well 50. Under centrifugal force and through suitable ducts (not shown) the pick-up oil is conducted to the usual bearing for the thread-carrier ll in the rotary hook l4.

In order to limit the quantity of 01] contained in the oil-well 60, the outer wall of said oil-well is provided with a discharge-port 64, illustrated in Fig. 2 of the drawing. The discharge-port 64 is preferably disposed at substantially the same level as the open lower end of the tubular scoop 62. The discharge-port 54 opens into an upwardly open pocket." formed in the bracket 25 to intersectin part the recon ll, thereby providing an openingin the side wall of the-recess 55 above therim of the oil-well 54. The bottomwallofthepocketllisconnectedbya duct 54 with the gear-clearance cavity 55 in'the bracket 2!, from which cavity the cm 011 drains into the bottom closure-plate 54. To induce discharge of oil from the oil-well 45, a pad 61 of felt or other suitable oil-absorbent material is preferably placed in'the oil-well 55 so as to be disposed in the region of the dischargeport 54. The pad 51 is preferably held below the rim of the oil-well I by means of a spring 58 confined in the pocket 55 by a pocketeclosure disk 69 set into the bracket 24. The flange ll functions as an oil-sling, and the oil thrown off by the flange II is free to drain into the pocket 85 through the opening in the side wall of. the recess 55 above the rim of the oil-well '55.

Instead of providing the lower ball-bearing 42 with the conventional abutment ring 42, as illustrated in Figs. 1 and 3, the upper ball-bearing 42 may be provided with an abutment-ring ll disposed in a circumferential groove in the outer race-ring, as shown in Fig. 2. The abutmentring I0 is made in'sections as illustrated in Fig. 4 and is applied to the upper ball-bearing 42 after the pinion-gear sleeve 24 has been inserted through the opening ofthe lower bracketwall. The abutment-ring II engages the upper wall 2i and is held thereagainst by the screwplug 45. This arrangement is a preferred modiiication in cases wherein it is desirable to positively resist an upward thrust imposed upon the pinion-gear sleeve 34 by the gears 55, 32.

As hereinbefore described, the pinion-gear sleeve 38, together with the ball-bearings 42 and the split abutment-ring 42 assembled therewith are inserted through the counterbcre opening 24 in the bracket 24 to seat the outer race-rings oi the ball-bearings 42 in the bracket-recesses 52 and 35. The screw-plug 45 is then threaded into the counterbcre 25 to force the abutment-ring 43 against the bracket-shoulder 44. The driving gear 50 is then shifted lengthwise of the shaft I into proper mesh with the pinion gear 24, whereupon the driving gear 55 is secured to the shaft 1. The rotary hook-shaft 20 is then passed downwardly through the sleeve ll of the pinion-gear, and the stem 24 of the eccentric is inserted upwardly into the bore of the hook-shaft 25; said shaft and eccentric-stem being secured together by means of the elongatedscrew 25. The rotary hook may now be conveniently timed with respect to its needle I 2, whereupon the sleeve 24 may be detachably secured to the hook-shaft 24 by means of the set-screw 21. V

This arrangement not only provides convenient means for assembling and accurately timing the rotary hock, but it has the additional and outstanding advantage of providing for removal and replacement of the rotar hook and its shaft without necessitating removal of the end-closure plate 41 of the bracket 25, and without disturbing the intermeshing relation of the driving and driven gears 55, 35. In order to remove the hook and its shaft 20, it is merely necessary to loosen the set-screw 21 from the hook-shaft and to unthread the screw 2 from the stem 24 of-the eccentric 25. After removal of the hook and its shaft, the pinion 24 remains in mesh with its driving gear 58 and the pinion-gear sleeve 24 remains in its proper position in the bracket 2!, inasmuch as said sleeve is coniinedby the bracket 1 29 against bodily sidewise movement.

Consequently, it is a simple matter to insert another hook and hook-shaft into the properly positioned pinion-gear sleeve 38.-

While only one rotary hook mechanism is illustrated in the drawing, it is to be understood that the sewing machine contains a similar rotary hook mechanism for cooperation with the left hand needle I2,

Having thus set forth the nature of the invention, what I claim herein is:

1. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket havin spaced walls providing therebetween a gearclearance cavity,- ball-bearings disposed in said walls of the bracket, a tubular sleeve rotatably Journaled in said ball-bearings, a pinion-gear carried by said sleeve and disposed between said walls, a rotary-hook carrying shaft disposed within and detachably secured for rotation with said sleeve, and means including a driving gear in engagement with said pinion-gear for rotating said shaft.

2. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket having spaced walls provided with coaxially disposed annular openings, ball-bearings seated in the respective openings of said walls, a tubular sleeve having opposite ends thereof rotatably journaled in said ball-bearings, said sleeve being provided between said walls with a pinion-gear smaller diametrically than one, of said openings, and a rotary-hook carrying shaft disposed within and detachably secured to said sleeve for rotation therewith.

3. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket having spaced walls each of which is provided with an annular opening, a tubular sleeve having the opposite ends thereof extendinginto the openings of said walls, a pinion-gear carried by said sleeve between said walls, ball-bearings including inner race-rings mounted upon the opposite ends of said sleeve and complemental outer race-rings seated in the respective openings of said walls, and a rotary-hook carrying shaft disposed within and detachably secured to said sleeve for rotation therewith.

4. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket having spaced walls each of which is provided with an annular opening, a tubular sleeve having the opposite ends thereof disposed in the openings of said walls, a pinion-gear carried by said sleeve between said walls, ball-bearings including inner race-rings mounted upon the opposite ends of said sleeve and complemental outer race-rings seated in the respective openings of said walls, means including an abutment-ring carried by the outer race-ring of one of said ball-bearings and secured against said bracket for holding said sleeve against endwise movement, and a rotaryhook carrying shaft disposed within and detachably secured to said sleeve for rotation therewith.

5. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket having spaced walls provided with coaxially disposed annular openings, a tubular sleeve provided with a pinion-gear disposed between said walls, said sleeve having the opposite ends thereof extending into the openings of said walls, ball-bearings including inner race-rings mounted upon said sleeve at opposite sides of said pinion-gear and complemental outer race-rings seated in the respective openings of said walls, one of said outer race-rings being externally provided with a circumferential groove, a sectional abutment-ring disposed in said circumferential groove, means engaging one of said outer race-rings for clamping said abutment-ring against one of the walls of said bracket, and a rotary-hook carrying shaft disposed within and detachably secured to said sleeve.

6. Rotary-hook mechanism for sewing machines, comprising, a supporting bracket having spaced walls provided with coaxially disposed annular openings, a rotary-hook carrying shaft rotatably journaled in said openings of the bracket, and a pinion-gear detachably secured upon said shaft and disposed between said walls, said pinion-gear having a hub confined by said bracket independently of said shaft against bodily sidewise movement.

WALTER MYERS. 

